There isn't any anomaly, the GDS is pricing the fare properly based on the currency selected and the exchange rate used.

To start, if you look at the Routing Rules, you'll see the base fare of AONE6 ex-KRT is SDG 26500.00

Next, you look at the conversion rates the GDS is using (part of the meta data returned to us):

"RATE USED IS BSR 1 SDG - 0.3724395 USD"
Which means 1USD = 2.685 SDG, which means the price in USD should be shown as USD $9870, which as you noted it is, so the USD price is correct.

Now if you request the fare in AUD you get:

"RATE USED IS ICH 1 SDG - 0.3048967 AUD"
Which means 1AUD = 3.28 SDG, which means the price in AUD should be AUD $8080, which it is, so that is correct as well.

It looks like the GDS is using the SDG->USD Bankers Selling Rate spot price (BSR) for showing the fare in USD (like AA is). However when requested in AUD, it is using the IATA Clearing House (ICH) rate for SDG->USD then converts USD->AUD since it couldn't determine a BSR for SDG->AUD directly.

If you Google "ICH BSR exchange rate" you'll find some documents that explain how the GDS tries one then the other when converting fares. As per chewy3's note, it looks like Sabre just uses the ICH rate across the board, which is more consistent but less accurate (as per AA's results).